Guiding, floating, and cementing device for well casings



Feb.'1 8, 1930. R. c. BAKER 1,743,007

GUIDING, FLOATING; AND CEMENTING DEVICE FOR WELL CASINGS Original Filed Nov. 23, 1927 Reuben C. Bake);

dew/M1 Patented Feb. 18, 1930 PATENT OFFICE BEUBENQ BAKER, O1! COALINGA, CALIIORNIA GUIDING, FLOATING, AND CEHENTING DEVICE FOR WELL CASINGS Original application filed November 23, 1927, Serial No. 335,204. Divided and this application filed December 26, 1929.

This application is a. division of my copending application Ser. #235,204 filed Nov.

The invention relates to deep well drilling 5 equipment and particularly pertains to a floating and cement device for use in floating a string of easing into a well and then cementing the well.

Prior to my invention, floating and cementing devices have been provided which were capable of guiding the casing into place and at the same time permit the casing to be floated into the hole. These devices were fitted with back pressure valves designed to permit cement to be ejected from the casing after it had been set in place in the well but' prevented the return of the cement into the casing. It has been common practice to make these floating shoes hollow and of cast iron so that they could be readily broken or drilled out after the casing has been properly cemented in. I

These prior devices have not proven entirely satisfactory for the reason that when. large casings were floated in place, the walls of the plug had to be comparatively thick to withstand the tremendous pressures encountered. Therefore, after the plugs were broken up considerable metal was left in the bot: tom of the hole. This metal had a very injurious effect on the drilling tools, particularly, the drilling shoe of core barrels run in to take a core after the casing had been set into place.- Such plugs as above described, are shown in patents issued to William Mc- Laine dated April 29, 1924, #1,491,915 and Reuben C. Baker dated Nov. 3, 1925, #l,559,662. L It is the principal object of the present invention to overcome the disadvantages of these prior structures by providing an improved fioating and cementing device formed principally of friable non-metallic material which will be nonsinjurious to thedrill-ing tools when removing it from the casing to continue the drilling operations.

In carrying out this object into practice, I provide a tubular steel sleeve which is adapted to be connected to the string as in common practice. This shoe is fitted with a Serial No. 416,659. 1

plug formed of cementitious or other suitable non-metallic material cast directly therein. The plug is formed with a valve passageway through which cement may be ejected. This passageway is controlled by a valve so that cement may be discharged from the casing through the plug, but cannot return from the hole intothe casing. v

One form which the invention may assume 1s exemplified in the following description and illustrated by Way of example in the accompanying drawings, in which:

Fig.1 is a central vertical section through a floating and cementing plug embodying the preferred form of my invention.

Fig. 2 is a view in end elevation of the device.

Referring more particularly to the accompanying drawings 10 indicates a hollow cylindrical member preferably formed of steel. This member is interiorly threaded as at 11 so that it may be connected to a string of well casing. Between the threaded portion 11 and the lower end of the member its interior surface is formed with annular locking grooves 12.

Cast within this lower end of the member and embedded in the locking grooves 12 is a plug 14. This plug 14 is formed of cementitious material. After the plug has been cast 50 into the cylindrical member the plug and cylinder are inseparably united by the connections thus formed. The lower end of the plug is spheroidal and of a diameter equalling the exterior diameter of the cylindrical member. Thus, the lower portion of the plug 14 will be semi-spherical and will project below the lower end of the shoe. This projecting portion of the plug 14 will act to guide the casing into place when it is lowered into the hole. This is quite important as it is often necessary to pass the casing downwardly through a line of casing or through an open hole which is often drilled through hard substances, such a? shell or a very hard strata of clay and the 95 1i e.

This feature is described and claimed in my e o-pending application Serial #235,204 of which this application is a division.

As the plug is formed of cementitious maion terial, should it be damaged during its travel downwardly into the hole, it will not render the entire device inoperative as considerable of the plug may be broken away without seriously impairing its usefulness. This is quite the contrary to prior devices which were made of cast iron and fitted with a small valve of the poppet type. In the event these plugs were damaged during their travel into the hole, their value in floating the easing into place immediately ceased because fluid was permitted .to enter the casing and the entire weight of the casing was thrown upon the derrick, making it necessary to remove the entire casing from the well and fit a new plug thereto.-

.In the present instance, however, should the entire lower portion of the plug be broken away, the cylindrical member will still remain plugged permitting the casing to be floated into place. i

It is obvious therefore that as a floating and guiding plug, the present invention has considerable merit as it is shaped to guide thecasing and so constructed that it will. not be rendered useless if parts thereof are broken away during its travel into the hole.

In order that the plug may be used to cement through after the casing has been lowered into the hole, the plug is formed with a central valve chamber 15. At the upper end of this chamber I provide a valve 16 of friable material such as bakelite or hard rubber. This valve plate 16 is formed with a central valve opening 17 which is in register with a passageway 18 extending from the valve plate through the top of the plug.

Around the opening 17 in the valve plate 16 is a valve seat 19 with which a buoyant spherical valve 20 is adapted to cooperate to control communication between the interior of the casing through the passageway 18 and the valve chamber 15. This spherical valve 20 is formed of a non-metallic substance such as wood, rubber, or other suitable composition of a specific gravity, causing it to float in fluid cement and a similar substance.

It is seen that when this valve 20 is in its upper position, it will seat on the valve seat 19 and interrupt the passage of fluid through the plug. When in its lower position, however, fluid may pass from the interior of the casing through the passageway 18, and thence into the valve chamber 15. From the valve chamber 15, the cement or other substance may pass through the plug through ports or passages 21 extending through the end of the plug from the valve chamber 15.

From the drawings it will be seen that the chamber 15 is of such cross section to prevent the valve 20 from closing either of the four ports 21.

A disk of bakelite or other non-metallic friable material form the lower end of the valve chamber 15. This plateis formed with openings in register with the ports or passages 21 so that they will communicate with the valve chamber 15.

The plates at the top and bottom of the valvechamber are both considerably larger in diameter than the valve chamber 15 so that their marginal edges will be embedded within that portion of the plug surrounding the valve chamber. These plates are sup-- ported in place during the casting of the plug so that after the cement has set they will be firmly held in place.

In operation of the device. the floating and cementing plug is constructed as shown in the drawings and the material forming the plug is preferably cementitious. After the plug has been fitted to the casing, the latter is inserted into the well and the fluid in the well enters the valve chamber 15, causing the valve 20 to rise and. seat on the valve seat 19, preventing the fluid from passing into the well casing. Thus the casing may be floated into the Well and its buoyancy will partially relieve the derrick of the weight of the casing.-

After the casing has been set into place, cement is pumped downwardly through the casing under pressure or by any other suitable method. The pressure of the cement on the valve 20 will cause the same to be unseated, permitting the free passage of the cement through the plug. After the proper amount of cement has been ejected into the well through the plug. the pressure in the cas ing is relieved and the valve 20, due to its buoyancy. will rise and seat on the valve seat 19 and prevent the cement in the well from returning into the casing. The valve will remain thus seated until the cement has set in the well and thereafter the entire plug may be drilled out, carried away with the circulating fluid. and the drilling of the well proceeded with.

As all of the portions of the plug obstructing the interior of the casing is made of friable non-metallic material, the drilling tools will not be injured in removing it. This is quite an advantage because in prior structures the amount of metal left in the hole after breaking out the plug was very injurious to drilling tools particularly to the core barrel.

From the foregoing it is obvious that I have provided a plug which will act as a guide in lowering the casing in the well, act to permit the casing to be floated into'place, and capable of permitting cementing operations to be carried on after the casing has been positioned.

It is desired to point out that the formation of the lower end ofthe plug is such that it will guide the casing in its downward travel in the hole. Also should the lower end of the plug become damaged or partially broken in its travel in the hole, it will not materially affect the operation of the plug as the valve will be in a position above the lower end of the casing shoe, and as the plug is comparatively solid and of friable material, portions of the lower end thereof may be broken ell during lowering without affecting the floating or cementing operations of the plug. This. as previously pointed out. is a considerable advantage over prior plugs which necessitated the removal of the string in the event the plug became broken.

The provisions of the friable plate at the top of the. valve chamber which is in corporated in the plug during the forming thereof is also important. The alvc plate 16 being formed with the valve seat insures a perfect valve seat which will not crumble. and which will be perfectly formed prior to the molding of the plu".

The method and mold for making the plug herein disclosed is described and claimed in my United States Letters Patent No. l. 720.- 878. issued July 16., 199.9.

lVhi'le I have shown the preferred form of my invention, it is to be understood that vari ous changes may be made in its construction by those skilled in the art without departing from the spirit of the invention. as defined in the appended claims. i

I claim:

1. A floating and guiding shoe comprising a tubular member adapted to be connected to the lower end of a string of easing. a-plug of cen'ient'itious material cast within the lower end of said member. a portion of said plug projecting beyond the lower end of said member, said portion being ot substantially the same diameter as the exterior diameter of the shoe at the point where the. two unite. said projecting portion being tapered inwardly and downwardly whereby it will form a guiding end, a passageway of comparatively small cross sectional area formed centrally and lougitudinally through said plug, and vatve means intermediate the ends of the passageway capable of preventing the passage of fluid upwardly through the plug and tubular member.

. 2. A floating device for well casings comprising a tubular member adapted to be connected to a well casing. a plug of cementitious material cast within said tubular member and inseparably united therewith. a passageway formed centrally and longitudinally through said plug, a valve seat in said passagcwav,

and a valve member buoyant in fluid cement co-operating with said "alve seat, said valve being adapted to permit fluid to be discharged downwardlythrough said passageway but not inthe opposite direction.

3. A device of the character described comprising a tubular member adapted to be secured to a string of easing, a plug of cement itious material formed within said tubular member, said plug having a valve chamber formed therein. a pair of flat members embedded at their peripheries within the plug and formingthe upper and lower ends of said valve chamber, said plug and upper flat member being formed with an intake passage- 'ay extending through the upper end of the,

plug, a valve seat on said upper fiat member surrounding said passageway, a valve within the chamber adaptedto co-operate with said valve seat to close said passageway, the lower end of said plug and said lower flat member being formed with fluid conducting means extending through the lower end of the plug, said means being unaffected by said valve.

4. A device of the character described comprising a tubular member adapted to be secured to a string of well casing, a plug cementitious material cast within said member, said plug having a central valve chamber formed therein, said plug being formed with a passageway through the upper end of said plug fromsaid chamber coaxially ofthe latter, a valve seat at the junction between the valve chamber and the said passageway, said plug being .tormed' with a plurality of passagcways extending from said chamber through the lower end ot'the plug, said latter passagcway being positioned at eccentric points relative to the center of the chamber, and a spherical buoyant valve member disposed within said chamber and adapted to co-operate with the valve seat to close the passageway from the chamber through the upper end of the plug.

5. A device of the character described comprising a tubular member adapted to be secured to a well casing. a plug of cen'ientitious material formed within said tubular member to plug the same, a. central valve chamber formed within the plug, a flat member of non-metallic material embedded at its periphery within the plug and forming the upper end of said chamber. said plug being formed witha passageway extending from the chamber through the flat member and upper end of the plug. said flat member being formed with a valve seat surrounding said passageway, a buoyant valve member within the chamber adapted to co-operate with said valve seat to close said passageway, said plug being formed with a plurality of lower passageways extending from the lower end oi said member through the lower end of the pl ug, the position of said lower passageways at the point they join the valve chamher being such that the valve member cannot obstruct the passage of fluid between the chamber and said passageways.

(t. A device of the character described comprising a. cylindrical member, a plug of cementitious material cast in said member and adapted to plug a well casing, said plug having a valve chamber formed coaxially therein. said plug being formed with a fluid passageway extending coaxially through the upper end of said plug from said chamber, said plug being formed with fluid conducting means extending coaxially from the lower end of said chamber through the lower end of the plug, and a buoyant ball valve member disposed within said chamber and adapted to close the passageway from the chamber through the upper end of the plug when fluid pressure enters said chamber through the lower end of the plug.

7. A device of the character described comprising a cylindrical member adapted to be connected with a well casing, a plug of cementitious material cast in said member and inseparably connected therewith, said plug having a Valve chamber formed therein about the axis thereof, said plug being formed with an upper fluid passageway extending coaXially through the upper end of said plug from said chamber, a flat member interposed between the chamber and said passageway and embedded at its peripheryin theplug, said flat member being formed with an opening surrounded by a valveseat in alignment with said upper passageway, said plug being formed with fluid conducting means extending from the lower end of said chamber through the lower end of said plug, and a buoyant ball valve member disposed within said chamber andadapted to co-operate with said seat in obstructing the passageway of fluid from the chamber through the upper end of the plug when fluid pressure enters the chamber through the lower end of the plug, said ball valve being incapable of obstructing the passage of fluid between the valve chamber and the -fluid conducting means.

REUBEN C. BAKER. 

